Machines are known, which roughen or dress the upper surface of a heel by means of a roughening brush, which rotates around an axis perpendicularly to the work-surface of said brush and the upper surface of the heel is roughened by the circumferential surface of said brush. During this procedure, the heel is clamped while being roughened, with its upper surface exposed to said roughening brush; the known machines, in practice, have not proven satisfactory since the shoe-heel periphery is often mutilated and the heel does not seat properly on the shoe-upper or adhesive may leak past mutilated heel-margins.